JPH0131738B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a communication line network configuration system comprising a center device, a line concentrator, and a group of slave stations connected to the line concentrator.

Generally, in online systems such as traffic control systems, the system is configured by using communication lines between center equipment and terminal equipment. On the other hand, as the system expands, there is a demand for an economical line network configuration, and one method to meet this demand is to aggregate a plurality of terminals with a line aggregation device. Furthermore, line aggregation methods include multi-drop and loop methods. The general loop system line network configuration is shown in Figure 1, in which a center device 1 and a plurality of line concentrators 2a...2n
Further, slave stations 3a ₁ . . . 3ak, . _. . , 3n 1 . In such a line network configuration, as shown in FIG. 9, the line concentrator becomes large-scale, and the line network as a whole becomes expensive.Also, there is a disadvantage that transfer delays occur due to buffer storage in the line concentrator. It was hot.

An object of the present invention is to eliminate the above-mentioned conventional drawbacks, and to provide a communication line network configuration system that is economical and does not cause transfer delays.

In order to achieve the above object, the communication line network configuration system of the present invention includes a hybrid transformer in the line concentrator, but the other parts of the line concentrator have the same configuration as the slave stations, and the center equipment The transmission from the terminal station to the line concentrator is performed at the center frequency 1, and from the final terminal station of the slave station group, the center frequency
A signal with a center frequency 2 different from 1 is generated, and this signal with a center frequency 2 is transmitted to the center equipment via the hybrid transformer of the line concentrator.

According to this invention, since a hybrid transformer is used for the line concentrator and the other parts have the same configuration as the slave station, there is no need to make the line concentrator large-scale, and the line network as a whole can be constructed at low cost. Also,
Since the configuration of the line concentrator is the same as that of the slave station, a highly flexible local network configuration is possible and no transfer delay occurs due to buffer accumulation processing.

The present invention will be explained in detail below with reference to embodiments shown in the drawings.

FIG. 3 is a block diagram schematically showing a communication line network configuration according to an embodiment of the present invention.

In FIG. 3, 11 is a center device, 12 is a line concentrator, and 13a, 13b, and 13c are slave stations. In this embodiment, the line concentrator 12, the slave station 13a,
Four terminal devices are connected by 13b and 13c. 14 is a hybrid transformer included in the line concentrator 12, which transfers the signal of center frequency 1 transmitted from the center device 11 to the line concentrator 12,
The signal is transmitted to the local side of the slave stations 13a, 13b, and 13c, and the signal of center frequency 2 generated at the final terminal station 13c of the loop is transmitted to the center device 11. The line concentrator 12 is a hybrid transformer 1
The other parts except 4 are slave stations 13a, 13b, 13
It has the same configuration as c. The same components as the slave station include a DEM (duplex modulation section) 15, a transmission control section 16, a processing section 17, and a MOD (modulation section) 18. The slave stations 13a, 13b, and 13c also have the same configuration as the line concentrator 12 except that they do not have a hybrid transformer, but only the slave station 13c connected to the final end of the transmission loop has a center frequency of the signal to be sent out.
It is distinctive in that it is different from the center frequency 1 of the input signal.

The transmission control section 16 of each terminal device 12, 13a, 13b, 13c is shown in more detail in FIG. In FIG. 4, reference numeral 20 denotes an identification control unit that identifies a GA signal, which will be described later. 21 is a 1-bit delay circuit, 22 is a switching circuit, 23 is a buffer,
24 and 25 are AND gate circuits, 26 is an OR gate circuit, and 27 is an inverter.

Next, the operation of the embodiment shown in FIGS. 3 and 4 constructed as above will be explained.

First, the center device 11 is set as the primary station in Fig. 5a.
A signal shown in is transmitted to the slave station including the line concentrator 12. F shown in FIG. 5a indicates a flag field, which specifically consists of 01111110. CA
The common address field consists of 11111111. C is a control field into which a control command is input.
GA is a go-ahead signal and consists of 01111111. In the end, the polling frame from flag field F to flag field F and GA
A signal consisting of 01111111 is sent from the center device 11 to 1
It is transmitted to the line concentrator 12 as the second slave station.
The line concentrator 12 is shown in FIG. 5a from the center device 11.
In response to the signal shown in FIG. 6, processing operations in accordance with the control flow shown in FIG. 6 are performed. That is, in step 30, an information signal from the center device 11 is received. Then, in step 31, the information signal is identified, and in step 32
It is determined whether GA is detected after the final F.
If GA is not detected, repeat steps 32 -> step 31 -> step 32 until GA is detected after the last F. If GA is detected after the final F, the judgment is
Move to step 33 with YES. In step 33, it is determined whether there is transmission information. In the example shown in FIG. 5, there is no information sent from the line concentrator 12, so the determination is NO.
Then, the process moves to step 36, and following the final step F, the GA is sent to the next slave station, that is, the second slave station 13a.
In the end, the signal sent from the center device 11 is
DEM15 of the line concentrator or first slave station →
1-bit delay circuit 21 → switching circuit 22 → AND gate 25 → OR gate 26 → MOD 18,
The signal is sent to the next second slave station 13a. As shown in FIG. 5c, the signal is delayed by one bit from the information signal sent from the center device 11, but there is no change in content. Second slave station 13a
The slave station also operates in the same way as the first slave station, that is, the line concentrator 12, and does not output its own transmission signal, so it transmits the same signal to the next third slave station with a one-bit delay, as shown in Figure 5d. It is sent to the slave station 13b.
Since the third slave station 13b has a transmission request, it proceeds in the same way as the other slave stations from step 30 to step 32 in FIG. is YES, and the process moves to step 34, where GA is converted to F. Then, in step 35, the slave station 13b itself transmits the data frame A3.CI.
Send FCS.F. Note that here, A3 is the third slave station address, and I is the transmission data from the third slave station. Since the transmission data is inserted from the third slave station in this way, the fourth slave station 13
The information signal given to c is delayed by 1 bit from the information signal entering the third slave station 13b, as shown in FIG. . Since the fourth slave station 13c does not send data to be transmitted from itself, the fifth slave station 13c
As shown in the lower part of Figure e, the information signal input to the fourth slave station is derived in the same form with a delay of 1 bit. Note that the fourth slave station 13c puts this information signal on a signal with a center frequency of 2, and transmits it to the hybrid transformer 1.
4 to the center device 11. As a result, the center device 11, that is, the primary station receives the information signal shown in FIG. 5f.

[Brief explanation of drawings]

FIG. 1 shows a configuration network of a loop type communication line, FIG. 2 is a block diagram showing a conventional line concentrator, and FIG. 3 is a block diagram showing an outline of a communication line network configuration according to an embodiment of the present invention. FIG. 4 is a diagram showing a specific circuit of the transmission control section of the slave station of the embodiment shown in FIG.
FIG. 5 is a diagram showing a specific example of transmission/information signals for explaining the operation of FIG. 3, and FIG. 6 is a diagram showing a control flow of the slave station of the embodiment shown in FIG. 11... Center equipment, 12... Line concentrator, 1
3a, 13b, 13c...Slave station, 14...Hybrid transformer, 15...DEM, 16...Transmission control unit, 17...Processing unit, 18...MOD.

Claims (1)

[Scope of Claims] 1. A configuration method of a communication line network consisting of a center device, a line concentrator, and a group of slave stations connected to the line concentrator in a loop, wherein the line concentrator includes a hybrid transformer and other devices. has the same configuration as the slave station group, transmission from the center equipment to the line concentrator is performed at center frequency 1, and a signal of center frequency 2 different from center frequency 1 is transmitted from the final terminal station of the slave station group. A system for configuring a communication line network, characterized in that the transmission from the line concentrator to the center equipment is transmitted at a center frequency of 2 via the hybrid transformer.